Coupled Atmosphere–Ocean Reconstruction of the Last Millennium Using Online Data Assimilation
Coupled Atmosphere–Ocean Reconstruction of the Last Millennium Using Online Data Assimilation
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DOI：
10.1029/2020pa003959
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发表时间：
2021-03
影响因子：
3.5
通讯作者：
W. Perkins;G. Hakim
中科院分区：
文献类型：
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作者：
W. Perkins;G. Hakim
我们使用在线数据同化将来自大气-海洋耦合动力学的线性逆模式的信息与代理记录相结合，以创建过去一千年来大气和海洋场的新的年度分辨率重建。对重建的海表面温度和0-700m海洋热含量的仪器验证表明，大范围的正空间相关，以及全球平均和大尺度大气变率模式指数的高度相关(∼0.6-0.9)。与以前的重建相比，在线重建显示了全球和半球的平均水平，几乎没有千禧年的趋势，早期(1000-1400C.E.)全球平均温度∼降低了0.25K-0.5K。早期(1000-1250 C.E.)平均气温的空间异常差异之后(公元1400-1700年)期间，欧洲高纬度地区出现暖异常，热带条件凉爽，与先前的评估部分一致。在线数据同化为气候代理信息提供了动态记忆，它的加入被证明是充分描述0-700m海洋热含量十年至百年尺度变率的关键。此外，气候预报为大气-海洋相互作用提供了基于模型的物理约束，在可用于同化的替代信息较少的早期阶段，这种约束变得越来越重要。
We use online data assimilation to combine information from a linear inverse model of coupled atmosphere‐ocean dynamics with proxy records to create a new annual‐resolution reconstruction of atmosphere and ocean fields over the last millennium. Instrumental validation of reconstructed sea‐surface temperature and 0–700 m ocean heat content shows broad regions of positive spatial correlations, and high correlations (∼0.6–0.9) for global averages and indices of large‐scale modes of atmospheric variability. Compared to previous reconstructions, the online reconstructions show global and hemispheric averages with little‐to‐no millennial‐scale trend and global‐mean temperatures ∼0.25–0.5 K cooler during early periods (1000–1400 C.E.). The spatial anomaly differences of average temperature between an early (1000–1250 C.E.) and later (1400–1700 C.E.) period show warm anomalies over high‐latitude Europe and cool tropical conditions in partial agreement with previous assessments. The addition of online data assimilation, which provides dynamical memory to climate proxy information, is shown to be crucial for adequately characterizing decadal‐to‐centennial‐scale variability of 0–700 m ocean heat content. Furthermore, the climate forecasts provide model‐based physical constraints for atmosphere–ocean interaction, which become increasingly important during early periods when less proxy information is available for assimilation.